Description of the blood test:

Anti-Neutrophil Cytoplasmic Antibodies (ANCA) are autoantibodies that mistakenly target proteins inside white blood cells (neutrophils). When these antibodies bind to neutrophils, they trigger an inflammatory attack on the walls of small blood vessels throughout the body. This group of diseases is known as Systemic Vasculitis. The test distinguishes between two main patterns:

• cANCA (Cytoplasmic): Primarily targets Proteinase 3 (PR3).
• pANCA (Perinuclear): Primarily targets Myeloperoxidase (MPO).

What Does This Test Represent?

• Purpose: To diagnose and differentiate between various types of autoimmune vasculitis and certain inflammatory bowel diseases.
• Primary Use: Investigating unexplained fever, weight loss, skin rashes, or signs of kidney/lung damage.
• Method: Indirect Immunofluorescence (IIF) or Enzyme-Linked Immunosorbent Assay (ELISA).

Preparation Recommendations

• Timing: Blood should ideally be drawn in the morning.
• Fasting: Overnight fasting (8–12 hours) is recommended; plain water is allowed.
• Physical State: Avoid strenuous exercise and alcohol for 24 hours before the test.
• Special Rules: Inform your doctor about any medications, especially steroids or immunosuppressants, as they can lower antibody levels and lead to a false-negative result.

Factors Influencing the Result

• Infections: Certain chronic infections (like endocarditis or hepatitis C) can sometimes cause a positive ANCA result without vasculitis.
• Medications: Some drugs (e.g., propylthiouracil, hydralazine) can induce “drug-induced ANCA-associated vasculitis.”
• Non-specific inflammation: pANCA can also be positive in patients with Ulcerative Colitis or Primary Sclerosing Cholangitis.

When to Take This Test?

• Clinical Signs: Persistent respiratory symptoms (bloody nose, cough, shortness of breath), blood in the urine (proteinuria/hematuria), or “purpura” (purple spots on the skin).
• Importance: Early detection of ANCA is critical to prevent irreversible organ damage, particularly in the kidneys and lungs.

Medical Interpretation

• Crucial Note: A positive result is not a diagnosis on its own. It must be correlated with clinical symptoms and often a biopsy. Only a Rheumatologist or Nephrologist should interpret these results.
• cANCA/PR3 Positive: Strongly associated with Granulomatosis with Polyangiitis (GPA), formerly known as Wegener’s.
• pANCA/MPO Positive: Frequently associated with Microscopic Polyangiitis (MPA) or Eosinophilic Granulomatosis with Polyangiitis (EGPA), formerly Churg-Strauss.

Possible Additional Investigations

• Urinalysis: To check for kidney involvement (blood or protein in urine).
• Chest CT Scan: To look for lung nodules or bleeding.
• Kidney or Lung Biopsy: The gold standard to confirm vasculitis and assess tissue damage.
• CRP and ESR: Markers to measure the general intensity of inflammation.
• Consultation with a Rheumatologist.

When is the Next Step Meaningful?

• If ANCA is positive, the immediate next step is usually imaging (CT/MRI) or a biopsy of the affected organ to confirm the diagnosis and start aggressive immunosuppressive therapy.
• All medical decisions are based on the combination of antibody titers, clinical presentation, and histological (biopsy) findings.

👉 If necessary, you can discuss your test results with specialists such as a Rheumatologist (Doctors – TAMC) or a Nephrologist (Doctors – TAMC).